Key escrow

Key escrow (also known as a “fair” cryptosystem) is an arrangement in which the keys needed to decrypt encrypted data are held in escrow so that, under certain circumstances, an authorized third party may gain access to those keys. These third parties may include businesses, who may want access to employees' private communications, or governments, who may wish to be able to view the contents of encrypted communications. Key escrow (also known as a “fair” cryptosystem) is an arrangement in which the keys needed to decrypt encrypted data are held in escrow so that, under certain circumstances, an authorized third party may gain access to those keys. These third parties may include businesses, who may want access to employees' private communications, or governments, who may wish to be able to view the contents of encrypted communications. The technical problem is a largely structural one since access to protected information must be provided only to the intended recipient and at least one third party. The third party should be permitted access only under carefully controlled conditions, as for instance, a court order. Thus far, no system design has been shown to meet this requirement fully on a technical basis alone. All proposed systems also require correct functioning of some social linkage, as for instance the process of request for access, examination of request for 'legitimacy' (as by a court), and granting of access by technical personnel charged with access control. All such linkages / controls have serious problems from a system design security perspective. Systems in which the key may not be changed easily are rendered especially vulnerable as the accidental release of the key will result in many devices becoming totally compromised, necessitating an immediate key change or replacement of the system.